Publishing margins aren't that big
I'm not sure if the margins ever were, in fact, but Amazon's influence on the books market has ensured that the only way to survive in publishing, is by throughput. Amazon's brutal policy of simply returning copy that it didn't sell, meant that it could offload most of the risk and expense of print-runs back onto the publishers, while harvesting the profits of that throughput, for itself.
Now, this has meant that the book market has actually become much more diverse and interesting, than it ever was before - but it also means that book publishers have to work much harder, and take much bigger risks, to maintain the same, traditionally slim, margins.
With the Kindle, Amazon's business model was beginning to look positively evil. With no physical product to store, a monopoly-Amazon could dominate the market, simply by being able to hold each publiser to ransom, by threatening them with a:
'DELETE FROM inventory WHERE stock_id=' . $ASIN.
Their only expense was to maintain the database, and customers would pay to download content from it - at their own expense, onto a crappy, dedicated, locked-down electronic device, that Amazon had sold to them in the first place, and which Amazon still controlled.
But this is the greed of the Little Men: a greed that has to explain its evil plan, in great detail, to show how clever it has been.
Google's evil plan is so vast and devious, its hard to tell if it is actually evil. It will offer a business that frees the content from any device or medium, so that the Kindles will consigned to the back of the 'Cupboard of Redundant Thinking', alongside the LED calculators, Microcassette tapes, and daisywheel printer heads (still in their original packaging).
This is because Google's business model does not involve selling content - indeed it's predicated upon the idea of as much of the world's content being freely available and unlocked, as possible. The Google business model is based around knowing what content its users are interested in. (They don't want to own the books: they want to own the fact that you are interested in the books, because that fact is potentially much more valuable.)
Amazon does this, already, of course, but it hasn't the sort of scale that Google can dream of. Amazon is still a website - that you have to go to - whereas Google is slowly becoming the entire Web.
A very big river can shift a lot of water in a very visible way, but an ocean current dosn't have to move its water very fast, at all, to generate much more actual throughput.